<div ng-controller="PanelDemoCtrl as pc">
    <wi-panel heading="点击头部展开"
              collapsible
              collapsed
              is-open="isopen">
        <p>collapsible 设置可以通过点击头部展开</p>
        <p>collapsed 设置初始折叠</p>
    </wi-panel>
</div>